Primdahl, Karoline G.Aursnes, MariusWalker, Mary E.Colas, Romain A.Serhan, CharlesDalli, JesmondHansen, Trond V.Vik, Anders2017-01-032016Primdahl, Karoline G., Marius Aursnes, Mary E. Walker, Romain A. Colas, Charles N. Serhan, Jesmond Dalli, Trond V. Hansen, and Anders Vik. 2016. “Synthesis of 13(R)-Hydroxy-7Z,10Z,13R,14E,16Z,19Z Docosapentaenoic Acid (13R-HDPA) and Its Biosynthetic Conversion to the 13-Series Resolvins.” Journal of Natural Products 79 (10): 2693-2702. doi:10.1021/acs.jnatprod.6b00634. http://dx.doi.org/10.1021/acs.jnatprod.6b00634.0163-3864http://nrs.harvard.edu/urn-3:HUL.InstRepos:29738931Specialized pro-resolving lipid mediators are biosynthesized during the resolution phase of acute inflammation from n-3 polyunsaturated fatty acids. Recently, the isolation and identification of the four novel mediators denoted 13-series resolvins, namely, RvT1 (1), RvT2 (2), RvT3 (3) and RvT4 (4), were reported, which showed potent bioactions characteristic for specialized pro-resolving lipid mediators. Herein, based on results from LC/MS-MS metabololipidomics and the stereoselective synthesis of 13(R)-hydroxy-7Z,10Z,13R,14E,16Z,19Z docosapentaenoic acid (13R-HDPA, 5), we provide direct evidence that the four novel mediators 1–4 are all biosynthesized from the pivotal intermediate 5. The UV and LC/MS-MS results from synthetic 13R-HDPA (5) matched those from endogenously and biosynthetically produced material obtained from in vivo infectious exudates, endothelial cells, and human recombinant COX-2 enzyme. Stereochemically pure 5 was obtained with the use of a chiral pool starting material that installed the configuration at the C-13 atom as R. Two stereoselective Z-Wittig reactions and two Z-selective reductions of internal alkynes afforded the geometrically pure alkene moieties in 5. Incubation of 5 with isolated human neutrophils gave all four RvTs. The results presented herein provide new knowledge on the biosynthetic pathways and the enzymatic origin of RvTs 1–4.en-USArticleJournal Article2017-01-0310.1021/acs.jnatprod.6b00634